Predictors of abnormal chest CT after blunt trauma: a critical appraisal of the literature

Implementation of an algorithm for chest imaging in blunt trauma decreases use of CT-scan: Resource management in a middle-income country

PURPOSE

Due to the low sensitivity of chest radiography, chest CT-scan is usually recommended for the evaluation of high-risk blunt trauma patients. Considering the radiation exposure and costs accompanying routine CT-scan, the aim of this study was to design and implement an evidence-based institutional algorithm for selective chest imaging in high energy blunt trauma patients and evaluate its effect on patient outcome and resource utilization.

METHODS

For this field trial, an institutional evidence-based algorithm for chest trauma imaging was designed according to existing data and expert panel. After final consent and ethic committee approval, the algorithm was integrated in the diagnostic flow sheet in the emergency department and patient data were collected from the pre- and post-implementation period.

RESULTS

One-hundred and sixty-five patients before algorithm implementation and 158 patients after that were included. Chest CT-scan was requested for 93% of patients in the pre-implementation group and for 73% in the post-implementation group (P<0.001). Length of stay in hospital was slightly shorter in the post-implementation group (p = 0.036), however, duration of stay in emergency room and ICU, pulmonary complications and mortality showed no significant difference.

CONCLUSION

Implementation of an algorithm for limiting chest CT-scan to a subgroup of patients with a higher risk of chest injuries can reduce radiation exposure and more useful distribution of resources without harming the patients. Each institution should use institutional guidelines and algorithms with respect to patient load, available resources and desired sensitivity for injury detection.

Arterial blood gas analysis utility in predicting lung injury in blunt chest trauma

BACKGROUND

thoracic trauma is one of the leading causes of death in all age groups and accounts for 25-50 % of all traumatic injuries. With the term lung injury in blunt chest trauma, we identified a spectrum of conditions: lung contusion, pneumothorax and haemothorax. The aim of this study was to evaluate the utility of arterial blood gas analysis parameters in predicting lung injury in blunt chest trauma.

METHODS

we included 51 patients presenting to the Emergency Department of "C.T.O." Hospital in Naples [Italy] for blunt chest trauma. The patients were assigned to the Lung Injury Group or to the Non-Lung Injury Group basing on CT scan findings. For each patient, we calculated the alveolar-arterial oxygen gradient [AaDO₂], the AaDO₂ augmentation, the arterial partial pressure of oxygen deficit [PaO₂ Deficit] and the ratio between arterial partial pressure of oxygen and fraction of inspired oxygen [P/F]. Areas under the curve [AUC] and receiver operating characteristic [ROC] curve were used to compare the performance of each different test in relation to the detection of lung injury in blunt chest trauma.

RESULTS

patients with lung injury had lower oxygen saturation, arterial partial pressure of oxygen, P/F and higher PaO₂ Deficit, AaDO₂, AaDO₂ augmentation than patients without lung injury. PaO₂ Deficit, AaDO₂ and AaDO₂ augmentation showed a good accuracy to predict lung injury in blunt chest trauma.

CONCLUSION

our study demonstrates that the combination of different arterial blood gas analysis variables may be a fast approach for identifying patients with lung injury in the setting of blunt chest trauma in the Emergency Department.

Routine versus selective chest and abdominopelvic CT-scan in conscious blunt trauma patients: a randomized controlled study

PURPOSE

CT-scan is increasingly used in blunt trauma, but the real impact on patient outcome is still unclear. This study was conducted to assess the effect of performing routine (versus selective) chest and abdominopelvic CT-scan on patient admission time and outcome in blunt trauma.

METHODS

Conscious and hemodynamically stable high-energy trauma patients were included (n = 140). Routine chest and abdominopelvic CT-scan was requested in addition to the conventional radiography and ultrasound for the intervention group and selective CT-scan according to clinical presentation was done for the control group. Patient admission times in the emergency room and surgery ward, complications, and performed surgical procedures were assessed. "Unsuspected injuries" defined as additional findings on CT-scan, which were not expected before CT-scan, were evaluated.

RESULTS

Admission time in the emergency ward and admission time in hospital were significantly shorter in the intervention group. Complications were similar in both groups. Abdominopelvic CT-scan in the intervention group revealed nine (7.8%) unsuspected injuries. All of these nine patients had also a positive clinical examination and injuries in other body regions. Chest CT-scan in the intervention group led to additional diagnoses in 17 patients (24.28%) leading to tube thoracostomy in 13 patients (18.57%).

CONCLUSION

Routine chest and abdominopelvic CT-scan in conscious blunt trauma patients decreases the hospitalization time, but has no impact on patient outcome and probably might lead to overtreatment of occult injuries. The option of using a selective approach should be further evaluated to decrease radiation exposure and facility overuse.

Prediction of blunt traumatic injuries and hospital admission based on history and physical exam

BACKGROUND

We evaluated the ability of experienced trauma surgeons to accurately predict specific blunt injuries, as well as patient disposition from the emergency department (ED), based only on the initial clinical evaluation and prior to any imaging studies. It would be hypothesized that experienced trauma surgeons' initial clinical evaluation is accurate for excluding life-threatening blunt injuries and for appropriate admission triage decisions.

METHODS

Using only their history and physical exam, and prior to any imaging studies, three (3) experienced trauma surgeons, with a combined Level 1 trauma experience of over 50 years, predicted injuries in patients with an initial GCS (Glasgow Coma Score) of 14-15. Additionally, ED disposition (ICU, floor, discharge to home) was also predicted. These predictions were compared to actual patient dispositions and to blunt injuries documented at discharge.

RESULTS

A total of 101 patients with 92 blunt injuries were studied. 43/92 (46.7 %) injuries would have been missed by only performing an initial history and physical exam ("Missed injury"). A change in treatment, though often minor, was required in 19/43 (44.2 %) of the missed injuries. Only 1/43 (2.3 %) of these "missed injuries" (blunt aortic injury) required surgery. Sensitivity, specificity, and accuracy for injury prediction were 53.2, 95.9, and 92.3 % respectively. Positive and negative predictive values were 53.8 and 95.8 % respectively. Prediction of disposition from the ED was 77.8 % accurate. In 7/34 (20.6 %) patients, missed injuries led to changes in disposition. "Undertriage" occurred in 9/99 (9.1 %) patients (Predicted for floor but admitted to ICU). Additionally, 8/84 (9.5 %) patients predicted for floor admission were sent home from the ED; and 5/13 (38.5 %) patients predicted for ICU admission were actually sent to the floor after complete evaluations, giving an "overtriage" rate of 13/99 (13.1 %) patients.

CONCLUSIONS

In a neurologically-intact group of trauma patients, experienced trauma surgeons would have missed 46.7 % of the actual injuries, based only on their history and physical exam. Once accurate diagnoses of injuries were completed, usually with the help of CT scans, admission dispositions changed in 20.6 % of patients. Treatment changes occurred in 44.2 % of the missed injuries, though usually minimal. Broad elimination of early imaging studies in alert, blunt trauma patients cannot be advocated.

Multidetector computed tomography of chest trauma: indications, technique and interpretation

Background

Chest traumas are a significant cause of mortality and morbidity, especially in the younger population.MethodsDiagnostic imaging plays a key role in their management. Multidetector computed tomography (MDCT) is the most important imaging method in this field. Its advantages include especially high speed and high geometric resolution in any plane.ResultsThe method allows us to view large parts of the body with minimal motion artifacts and to create accurate multiplanar and three-dimensional (3D) reformations, which make the diagnosis significantly more accurate. Because of its advantages MDCT has become the first-choice method in high-energy traumas.ConclusionThis article summarises the position of MDCT in the diagnostic algorithm of chest injuries, technical aspects of the examination and imaging findings in traumas of the individual chest compartments.

Teaching Points

• Diagnostic imaging plays a key role in the management of high-energy chest trauma.

• MDCT is the most important imaging method in this kind of injury, as detailed information can be acquired in a short acquisition time.

• Multiplanar and three-dimensional (3D) reformattings make the diagnosis significantly more accurate.

Multidetector-row computed tomography of thoracic trauma

Imaging in trauma patients has dramatically evolved since the advent of computed tomography (CT), particularly multidetector CT (MDCT) technology. Axial MDCT images of the body can be acquired in seconds and shown any plane, allowing immediate viewing and interpreting. These factors make CT an invaluable means to detect many injuries not previously visible by any other noninvasive imaging techniques. Potentially subtle, but significant, thoracic injuries such as pneumothorax, haemothorax, aortic injury, sternal and spinal fractures can be detected on MDCT easily. In this article, the author will discuss the use of MDCT in the diagnosis of various thoracic injuries.

Criteria for the selective use of chest computed tomography in blunt trauma patients

PURPOSE

The purpose of this study was to derive parameters that predict which high-energy blunt trauma patients should undergo computed tomography (CT) for detection of chest injury.

METHODS

This observational study prospectively included consecutive patients (>or=16 years old) who underwent multidetector CT of the chest after a high-energy mechanism of blunt trauma in one trauma centre.

RESULTS

We included 1,047 patients (median age, 37; 70% male), of whom 508 had chest injuries identified by CT. Using logistic regression, we identified nine predictors of chest injury presence on CT (age >or=55 years, abnormal chest physical examination, altered sensorium, abnormal thoracic spine physical examination, abnormal chest conventional radiography (CR), abnormal thoracic spine CR, abnormal pelvic CR or abdominal ultrasound, base excess <-3 mmol/l and haemoglobin <6 mmol/l). Of 855 patients with >or=1 positive predictors, 484 had injury on CT (95% of all 508 patients with injury). Of all 192 patients with no positive predictor, 24 (13%) had chest injury, of whom 4 (2%) had injuries that were considered clinically relevant.

CONCLUSION

Omission of CT in patients without any positive predictor could reduce imaging frequency by 18%, while most clinically relevant chest injuries remain adequately detected.

Primary pan-computed tomography for blunt multiple trauma: can the whole be better than its parts?

Single-pass, whole-body computed tomography (pan-CT) was proposed in the late 1990s as a new concept for the diagnostic work-up of severely injured patients. Since its introduction, it has led to considerable debate among clinicians and scientists, triggered by concerns about its immediate safety, questionable therapeutic advantages and exposure to radiation. However, it was recently shown that pan-CT scanning may be associated with a reduction in trauma mortality. In this article, we provide an overview of current knowledge of the value of this compelling concept. The diagnostic accuracy of multidetector row CT (MDCT) for clearing various anatomical regions in trauma patients is, at best, unclear. Little is known about the accuracy of pan-CT as a whole, which weakens statements about its effectiveness and prevents inferences about survival advantages. This last point may be explained by a stage-migration or "Will Rogers" phenomenon: Pan-CT increases injury severity by detecting lesions that would not have been recognized by conventional methods but still do not affect treatment decisions, thus artificially lowering the ratio of observed to expected deaths. In order to maintain the credibility of pan-CT technology for trauma, a rigorous, large-scale evaluation of its accuracy is required. Such an evaluation requires consensus about the definition of true and false positive and negative findings in the setting of blunt multiple trauma. In addition, triage criteria need to be refined to increase specificity and reduce the number of unnecessary scans.